Mechanical interlock

ABSTRACT

A mechanical interlock for preventing the operation of more than one of a pair of electrical contactors. The interlock includes for operation by each contactor a spring-biased plunger operable within a cylindrical cavity, no more than one plunger being operable at a time since the cavities through which the plungers operate obstruct each other just beyond the contactor deenergized position of each plunger.

D United States Patent w13,622,719

[72] Inventor Sherman G. Thomas [56] References Cited 1 UNITED STATES PATENTS 5 Qf 3;; 1970 2,803,969 8/1957 Hester 74/483 x z f 1971 2,398,656 4/l946 McFarland, Jr. 200/50 0 9 [73] Assignee General Electric Company Primary Examiner-Milton Kaufman Attorneys-John B. Sponsler, James C. Davis, Jr., Frank L. Neuhauser, Oscar B. Waddell, Joseph B. Forman and [54] MECHANICAL INTERLOCK Arnold E. Renner 4 Claims, 2 Drawing Figs. [52] US. Cl 2 222212% ABSTRACT: A mechanical interlock for preventing the SI I Cl "01h 9/20 operation of more than one of a pair of electrical contactors. [50] Fl; .ld 74/483 R The interlock includes for operation y each Contacmr a l e o arc C 5 spring-biased plunger operable within a cylindrical cavity, no

more than one plunger being operable at a time since the cavities through which the plungers operate obstruct each other just beyond the com-actor deenergized position of each plunger.

PATENT Enunv 23 [an SHEET 2 Biz FIGQ MECHANICAL INTERLOCK BACKGROUND OF THE INVENTION It is common practice to mechanically interlock contactors used in complex electrical mechanism and the like to safeguard property and personnel during switching operations, and the present invention is an improvement in such devices.

SUMMARY OF THE INVENTION plunger.

BRIEF DESCRIPTION OF THE DRAWINGS FIG.. 1 is a cutaway view of the mechanical interlock wherein the internal parts are exposed.

FIG. 2 is an assembly drawing showing the mechanical interlock mounted on a base between two contactors.

DESCRIPTION Referring to FIG. 1, a mechanical interlock is shown wherein two contiguous matching parallelepipeds are joined together to'form a housing consisting of a front half 11 and a rear half 13, a portion of the former being cut away to expose a major portion of a surface of rear half 13 abutting front half 11. Rear half 13 is shown with a corner removed along a straight line on surface 15 from the center of a side 19 to the center of an adjacent side 21, and with two semicylindrical transverse cavities 23 and 25 upon surface 15; cavity 23 extends perpendicularly from the center of the remnant of side 19, and cavity 25 extends perpendicularly from the remnant of side 21, cavities 23 and 25 intersecting at a 90 angle at a point 27 near the corner opposite the removed corner 17. The central portion of cavity 23 lying between side 19 and point 27 is enlarged to form a pocket 29, and the central portion of cavity 25 lying between side 21 and point 27 is enlarged to form a pocket 31.

The abutting surface of front half 11 (not shown) is a mirror image of surface 15, thus cavities 23 and 25 along with their respective pockets 29 and 31 become cylindrical when front half 11 is in place. A cylindrical rod 33 is slidably operable axially through cavity 23 and a cylindrical rod 35 is slidably operable axially through cavity 25, rods 33 and 35 each having an end projecting externally respectively from sides 19 and 21. The opposite ends of rods 33 and 35 are normally positioned adjacent to but not obstructing the intersection point 27. In this position, a peripheral groove 37 on rod 33 is urged to align with a point 41 just inside the end of pocket 29 nearer to side 19 by aspring 39, the spring 39 surrounding rod 33 within pocket 29. Spring 39 bears at one end against a retainer 43 which is shown in the preferred embodiment as an E-ring 43 inserted in groove 37, and at the other end against the end of pocket 29 nearer to point 27 to normally maintain the alignment of groove 37 with point 41. Also in this position, a peripheral groove 45 on rod 35 is urged to align with a point 47 just inside the end of pocket 31 nearer to side 21. A spring 49, surrounding rod 35 within pocket 31, bears at one end against a second retainer 45 which is shown in the preferred embodiment as an E-ring 51 inserted in the groove 45, and at the other end against the end of pocket 31 nearer to point 27 to normally maintain the alignment of groove 45 with point 47.

Referring now to FIG. 2, the mechanical interlock 10 may be applied, for example, to reversing contactors to prevent simultaneous contactor operation, the reversing contactors exemplified in FIG. 2 by Contactor l and Contactor 2. An arrangement is shown in FIG. 2 wherein the mechanical i'nter- 1015 disposed between Contactor 1 and Contactor 2 and is attached to a base 53 by screws 55. An insulated pin 57 on the armature 59 of Contactor 1 engages a slot 61 at one end of an angled arm 65, arm 65 rotating in a counterclockwise direction upon a pivot 67 when the contactor is energized, the armature 59 moving in the direction indicated by arrow A; the direction of the rotational movement of arm 65 is indicated by arrow B. The other end of arm 65 abuts 33 so that counterclockwise rotation of arm 65 depresses plunger 33. Contactor 2 has a similar arrangement for depressing rod 35, the arrangement differing only in the rotational direction of the angled arm on the pivot when the contactor is energized, the arm moving in a clockwise direction in this instance.

Referring now to FIGS. 1 and 2, simultaneous operation of Contactors 1 and 2 is prevented by the mechanical interference of rods 33 and 35 within the mechanical interlock 10. Energization of Contactor 1 before the energization of Contactor 2, for example, rotates arm 65 in a counterclockwise direction moving rod 33 axially through cavity 23, rod 33 thus obstructing point 27 to prevent rod 35 from passing through the same point. If, on the other hand, Contactor 2 is energized before Contactor 1, rod 35 will be moved axially through cavity 25 to obstruct movement of rod 33. Point 27 is cleared upon the deenergization of the energized contactor by the spring 39, in the case of rod 33, and by the spring 49 in the case of rod 35, urging respectively retainers 43 and 45 to return to their normal alignment with points 41 and 47.

What is claimed is:

1. An interlock including an engaging means for an operating member comprising a pair of plungers slidable disposed in transversely intersecting cavities within a mounting block; each cavity extending from said intersection to an external surface of said blocks; an end of each plunger extending beyond said surface for engaging an operating member to be provided an interlock; the opposite end of each plunger when operated obstructing operation of the other said plunger across said intersection; a spring normally biasing each said plunger toward its extended position; and an engaging means to link said plunger with said operating member; said engaging means being a pivotal-angled arm.

2. The invention according to claim 1 wherein said operating member is an electrical contactor.

3. The invention of claim 1 with the further provision that said biasing spring surrounds a portion of said plunger urging a retainer in a peripheral groove on the plunger against one end of a pocket for containing said plunger and said spring, thus positioning said plunger.

4. The invention of claim 1 and with the further provision of claim 9 wherewith said retainer is an E-ring.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,622,719 Dated November 23, 1971 Inventor(s) Sherman G. Thomas It is certified that error appears in the aboveidentified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, line 20, after "abuts" insert -rod-. Column 2, line 42, cancel "slidable" and substitute -slidably Column 2, line 61, cancel 9" and substitute 3. I

Signed and sealed this 9th day of May 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTISCHALK Attestlng Officer Commissioner of Patents 

1. An interlock including an engaging means for an operating member comprising a pair of plungers slidable disposed in transversely intersecting cavities within a mounting block; each cavity extending from said intersection to an external surface of said blocks; an end of each plunger extending beyond said surface for engaging an operating member to be provided an interlock; the opposite end of each plunger when operated obstructing operation of the other said plunger across said intersection; a spring normally biasing each said plunger toward its extended position; and an engaging means to link said plunger with said operating member; said engaging means being a pivotal-angled arm.
 2. The invention according to claim 1 wherein said operating member is an electrical contactor.
 3. The invention of claim 1 with the further provision that said biasing spring surrounds a portion of said plunger urging a retainer in a peripheral groove on the plunger against one end of a pocket for containing said plunger and said spring, thus positioning said plunger.
 4. The invention of claim 1 and with the further provision of claim 9 wherewith said retainer is an E-ring. 